This invention relates generally to emergency radio communications for law enforcement agencies and in particular to communications amongst police officers between vehicles and a central station.
Emergency radio communication systems of the type to which the present invention relates have been heretofore proposed as disclosed, for example, in U.S. Pat. Nos. 3,290,597, 3,699,443, and 3,723,876. U.S. Pat. Nos. 3,290,597 and 3,723,876, to Denny and Seaborn, respectively, disclose systems in which emergency communication is established between a police vehicle and a central station by use of a remote radio trigger device or portable transmitter carried by the police officer when leaving his vehicle. The remote radio trigger device initiates transmitting operation of the mobile, two-way radio in the police vehicle so as to broadcast a prerecorded message. In this fashion, the police officer and vehicle may be identified and assistance requested. Such prior systems require special recording equipment and extensive modification of the mobile radio equipment in the police vehicle. Further, the messages must be prerecorded at some earlier time or date by the police officer anticipating an emergency situation. Thus, the police officer must not only anticipate an emergency situation and have sufficient time within which to record a timely message but must follow certain operational procedures dictated by the equipment.
It is therefore an important object of the present invention to provide an improved type of emergency communication system which is simple to install and use and which embodies an operational mode that is more reliable in obtaining assistance for the police officer during emergency situations, without, however, adversely affecting use of the communication system for non-emergency situations.